Skin cancer and Parkinson's disease.

The report of an increased frequency of melanoma during the clinical development of rasagiline prompted a renewed interest in a possible association between skin cancer and Parkinson's disease (PD). The evaluation of this risk ended in a recommendation to perform a periodic dermatological examination as a follow-up measure of their treatment. The recognition of this safety concern lead to the need to clarify if the risk of skin cancer is indeed associated with PD and if levodopa or other anti-parkinsonian drugs might contribute to increase such risk. To answer these questions, we critically reviewed all clinical studies available concerning the association between skin cancer and PD. We found 26 studies on cancer occurrence in PD. The best data available suggest the risk of cancer is reduced in PD patients. However, specific cancers like thyroid and the female breast were reported at higher-than-expected rates. Additionally, it was suggested that PD patients have a higher frequency of melanoma and non-melanoma skin cancers than the general population. The data on non-melanoma skin cancer are less robust than the data on melanoma. Causal factors remain unknown. Due to the weak association between skin cancer and PD, no robust recommendation can be made regarding the need for periodic dermatological screening.